Enhanced Degradation of Diesel in the Rhizosphere of Lupinus luteus after Inoculation with Diesel‐Degrading and Plant Growth‐Promoting Bacterial Strains

The association of plants and rhizospheric bacteria provides a successful strategy to clean up contaminated soils. The purpose of this work was to enhance diesel degradation in Lupinus luteus rhizosphere by inoculation with selected bacterial strains: a diesel degrader (D), plant growth–promoting (PGP) strains, or a combination (D+PGP). Plants were set up in pots with the A or B horizon of an umbric Cambisol (ACamb and BCamb) spiked with diesel (1.25%, w/w). After 1 mo, the dissipation of diesel range organics (DRO) with respect to t = 0 (i.e., 1 wk after preparing the pots with the seedlings) concentration was significantly higher in inoculated than in noninoculated (NI) pots: The highest DRO losses were found in ACamb D+PGP pots (close to 15–20% higher than NI) and in BCamb D pots (close to 10% higher). The water‐extractable DRO fraction was significantly higher at t = 30 d (15–25%) compared with t = 0 (